Tag «Oscillators»

Direct Coupled Discrete Astable Multivibrator

This flip-flop circuit  is a free running/astable multivibrator one,  with bases and collector of both emitter biased transistor are directly coupled to each other.  Switching action is supported by means of capacitor in each emitter circuit.  This configuration produce a triangle waves at emitters. Since neither transistor can remain permanently cut off, then a free …

Variable Frequency And Duty Cycle Oscillator

A discrete oscillator circuit shown in the schematic diagram below is  a variable duty cycle and variable frequency oscillator, can be used to produce rectangular wave. This circuit has frequency range of 60 to 1,000 Hz. This circuit consist of one UJT (uni junction transistor) and two transistors that provide positive going output when emitter …

Scope’s Time Base Calibrator

A scope calibrator is a circuit that is used for calibrating the variable time base oscillator of general purpose scopes. This scope calibrator gives 100kHz reference, so if the scope is set to 10 cycles on 10 graticule divisions, then each division represents 10 microseconds or 100kHz. And each division will represent 1 Mhz or …

20 kHz Astable Multivibrator with Transistors

Astable multivibrator or oscillator circuit is based on positive feedback. We can design such circuit using op-amp, logic gates, or transistors. Here we can rely on single capacitor capacitor and resistor for the feedback inside op-amp like transistor circuit, which works over wide range of temperature, voltages and transistor gains. The stability is pretty good, …

2-MHz Frequency Standard With Dividers

This is an oscillator circuit that can be used for calibrating frequency counters, amateur receivers and frequency meters. This circuit is called 2MHz standard with dividers circuit. This circuit uses two crystals, 100kHz and 2 MHz.  Here is the schematic diagram of the oscillator part of the circuit: This circuit is then can be combined …